As ciarette smoking adversely affects vitamin C metabolism in humans, smokers need substantially more vitamin C intake than do non-smokers to achieve similar serum vitamin C concentration. To provide the basic information currently available for the determination of vitamin C requirement for Korean smokers, we investigated the differences the serum vitamin C values between smokers(n=53) and non-smokers(n=62) in relation to their intake of the vitamin through diet in 115 male college students, who had not been using vitamin C supplements. Dietary intakes of vitamin C were determined by a 24-hour recall, and serum vitamin C was determined using the 2, 4-dinitrophenylhydrazine method. The mean vitamin C intakes of smokers and non-smokers were consuming less than 75% of the Koeran RDA for vitamin c in their diet. Smokers consumed yellow and green leafy vegetables more often (P=0.02) and fresh fruits less often(P=0.006) than non-smokers. The mean serum vitamin C concentration of smokers consuming the same amounts of vitamine C as non-smokers, 64.3 umol/1, were 20% lower than for non-smokers, 80.1 umol/l(P<0.05). The risk of low serum vitamin C concentration (LoC) among smokers were 3.8% compared with 1.6% in non-smokers, and the odd ratio for LoC risk was 2.43. There were no correlations between dietary and serum vitamin C for smokers and non-smokers. It was concluded that smokers might require at least 20% more vitamin C to reach the same concentration comparable to non-smokers.